The whole floor is different on the AWD Suzuki Swift/Justy/Cultus. And the Swift-based Justy was never sold over here.
But things are easier on the 1988-1991 Civic Wagons! I can add a rear diff if I had the suspension and subframe from an AWD Civic Wagon. And with the extra torque of an electric motor, I could swap in a CRX HF drivetrain. But I wouldn't want to start such a project with the rust bucket I'm driving, it's too far gone to invest a lot of time into it.